Safety Not Guaranteed has all the hallmarks of a cult favorite: off-beat characters, a goofy premise and an emotional hook that resonates; the desire to go back in time, not for a big sci-fi deal like say, saving the world, but to feel better about one’s place in it. Touching, generous, sweet, this little slip of a movie puts you under some kind of spell.

Much of that has to do with the beguiling Aubrey Plaza, until now best known for her four seasons on NBC’s Parks and Recreation, where she plays April Ludgate, a teenager so gloomy it seems she must have been engineered by Tim Burton during a secret experiment to build an updated hipster model of Christina Ricci. In director Colin Trevorrow’s Safety Not Guaranteed she plays Darius Britt, a forlorn intern at the fictional Seattle Magazine who gets roped into a journalistic investigation of an intriguing want ad seeking a traveling companion. Weapons are needed, payment is only upon return and the time traveler admits to having only done it once before. Safety is not guaranteed.

Anyone who has ever set foot inside an alternative publication will recognize that this ludicrous story idea is also completely plausible. Even if lead writer Jeff (Jake M. Johnson—another breakout television star—Nick on the hit New Girl) only finds out that the author is a lunatic, the nature of his or her insanity could easily produce 5,000 words. “A little tongue-in-cheek investigation,” Jeff proposes. “I think it could be funny.” He packs up his research team of Darius and adorably nerdy Arnau (Karan Soni), a biology and life sciences major interning to add “diversity” to his resume, and takes them to the small Washington beach town where the ad originated.

The glib Jeff, who nurtures the perfect sprinkle of stubble on his chin, quickly reveals the true motivation for his pitch—he wants to visit another of the town’s residents, an old girlfriend named Liz (the wonderfully warm Jenica Bergere). They had a magical teenaged summer and he couldn’t be blunter about his goal: “I’m coming back to try to see her naked again.” When they meet, the time traveler, Kenneth (Mark Duplass) sees right through Jeff. “What is that smile?” he asks. “You don’t know pain. You don’t know regret.” The undercover reporting job falls to Darius instead.

She and Kenneth circle each other in a verbal pas de deux worthy of Merce Cunningham dancers. They’re playful, strange and gradually, flirtatious. From writer Derek Connolly’s narrated prologue, we know Darius is not an optimist. “I guess I remember being happy when I was a kid,” she says. “Back when you just naturally expect good things to happen.” But Kenneth awakens something in her, hope and even a belief in something as impossible as time travel. The scene where she reveals her genuine interest in going back in time to Darius is a miniature of heartbreak, an unexpected moment of poignancy from an actress who is generally a master of the ironic eye roll. The movie thrives on Darius’ growing tenderness toward Kenneth. He must be a quack — right? — but when he says “Our chemistry is starting to build” there’s real truth there. Duplass, so solid and earthbound, and Plaza, of the saucer eyes and fairy build, make an odd but captivating couple.

Safety Not Guaranteed is about regret: Jeff’s over a youthful fantasy he wants to bring into the present, Darius’ over a tragic loss and her unfeeling action just before it. Duplass, who honed his skills as writer/actor/director/producer in indie film (the so-called Mumblecore movement) and will appear in two other films this month (Your Sister’s Sister and People Like Us) may be playing an unstable man, but he and his dream of time travel provide the story’s unexpected stability. Kenneth is teaching them how to seize the moment in the present while looking for the past. Nothing is guaranteed and the surreal ending is not what you might have predicted, but if you’re lucky enough to be caught up in the movie’s mood — it’s not for everyone — it may just leave you smiling.

Mary Pols has been reviewing film and occasionally books for TIME since 2009. She has degrees from Duke University, where she studied art history, and the University of California Berkeley’s School of Journalism. She is the author of a memoir about untraditional parenthood. It was made into a short-lived television comedy where everything turned out traditionally.

Accidentally on Purpose: The True Tale of a Happy Single Mother is available for nearly nothing at various online bookstores and from boxes in Pols' barn.